#region Copyright notice and license

// Copyright 2015 gRPC authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#endregion

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using System.Threading;
using System.Threading.Tasks;
using Google.Protobuf;
using Grpc.Core;
using Grpc.Core.Utils;
using NUnit.Framework;
using Grpc.Testing;

namespace Grpc.IntegrationTesting
{
    /// <summary>
    /// Snapshottable wall clock stopwatch.
    /// </summary>
    public class WallClockStopwatch
    {
        long startTicks;

        public WallClockStopwatch()
        {
            this.startTicks = DateTime.UtcNow.Ticks;
        }

        public TimeSpan GetElapsedSnapshot(bool reset)
        {
            var utcNow = DateTime.UtcNow;

            long oldStartTicks;
            if (reset)
            {
                oldStartTicks = Interlocked.Exchange(ref this.startTicks, utcNow.Ticks);
            }
            else
            {
                oldStartTicks = this.startTicks;
            }
            return utcNow - new DateTime(oldStartTicks, DateTimeKind.Utc);
        }
    }
}
